Study of soil erosion risks using remote sensing in Ouergha River watershed (Morocco)

Abstract

The watershed Ouergha River located in the north of Morocco suffer from vegetation cover degradation, this geographic entity is experiencing intense water erosion linked to the combination of several natural factors, such as the roughness and abundance of rainfall and the predominance of soft geological formations. Human intervention in this vulnerable environment accentuates its fragility by the clearing and degradation of the vegetation cover and the cultivation of land with a steep slope. This work aims to map the spatiotemporal evolution of this degradation by using the spot and Landsat images and the Radar image over a period from 1990 to 2014 data and aims to model its processes of erosion. In fact, the analysis of satellite data identified six main types of land use (eau, foret, reboisement...). It has also shown that the most degraded soils aren't necessarily those with the greatest erosion rates over the past 15 years and that some soils that have developed well over time have become major exporters of sediments after clearing and cultivation. The comparison of the results of land use has highlighted the harmful impact of human practices on the acceleration of soil degradation. Human intervention, coupled to frequent and severe drought periods, remain the most important factors in the weakening and increasing vulnerability of soils to degradation. The results obtained by this approach made it possible to identify and monitor vulnerable areas at Ouergha watershed where interventions are needed to limit the processes of degradation of the soil and the natural environment.